1. Field of the Invention
The present invention relates to an imaging apparatus with a high resolution using, e.g., a pixel shift mode.
2. Description of the Related Art
In recent years, in various kinds of fields, there has been increased a demand for obtaining a high-sensitive high-definition image by an imaging apparatus using a fixed imaging element (which will be referred to as a CCD hereinafter). At present, the number of pixels realized by an imaging device such as a fixed imaging element is approximately several-million pixels. In order to obtain image data with ten-million or more pixels, a pixel shift mode disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 11-275408 is used.
The pixel shift mode performs imaging a plurality of number of times by slightly moving a CCD by a micro-motion mechanism employing a piezoelectric actuator. The micro-motion mechanism used in the pixel shift mode is disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2003-98059.
On the other hand, high sensitivity for fluorescent observation shooting is demanded in a digital camera for a microscope or the like. In order to realize a high-sensitivity camera, the signal-to-noise ratio is improved by, e.g., cooling the CCD. For cooling the CCD, there is used a so-called cooled CCD technique which directly or indirectly cools the CCD by utilizing a cooling element such as a Peltier element.
In an imaging apparatus using a micro-motion mechanism utilized in the pixel shift mode, not only high-definition image data is obtained, but high-sensitivity image data is also acquired. In such a case, a possibility of using the cooled CCD technique in the imaging apparatus is high. When the cooled CCD technique is used, however, a problem of radiation performance occurs in the imaging apparatus.